1 /* 2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.awt.dnd; 27 28 import java.awt.Component; 29 import java.awt.Cursor; 30 import java.awt.GraphicsEnvironment; 31 import java.awt.HeadlessException; 32 import java.awt.Image; 33 import java.awt.Point; 34 import java.awt.Toolkit; 35 import java.awt.datatransfer.FlavorMap; 36 import java.awt.datatransfer.SystemFlavorMap; 37 import java.awt.datatransfer.Transferable; 38 import java.io.IOException; 39 import java.io.ObjectInputStream; 40 import java.io.ObjectOutputStream; 41 import java.io.Serializable; 42 import java.security.AccessController; 43 import java.util.EventListener; 44 45 import sun.awt.AWTAccessor; 46 import sun.awt.AWTAccessor.DragSourceContextAccessor; 47 import sun.awt.dnd.SunDragSourceContextPeer; 48 import sun.security.action.GetIntegerAction; 49 50 51 /** 52 * The <code>DragSource</code> is the entity responsible 53 * for the initiation of the Drag 54 * and Drop operation, and may be used in a number of scenarios: 55 * <UL> 56 * <LI>1 default instance per JVM for the lifetime of that JVM. 57 * <LI>1 instance per class of potential Drag Initiator object (e.g 58 * TextField). [implementation dependent] 59 * <LI>1 per instance of a particular 60 * <code>Component</code>, or application specific 61 * object associated with a <code>Component</code> 62 * instance in the GUI. [implementation dependent] 63 * <LI>Some other arbitrary association. [implementation dependent] 64 *</UL> 65 * 66 * Once the <code>DragSource</code> is 67 * obtained, a <code>DragGestureRecognizer</code> should 68 * also be obtained to associate the <code>DragSource</code> 69 * with a particular 70 * <code>Component</code>. 71 * <P> 72 * The initial interpretation of the user's gesture, 73 * and the subsequent starting of the drag operation 74 * are the responsibility of the implementing 75 * <code>Component</code>, which is usually 76 * implemented by a <code>DragGestureRecognizer</code>. 77 *<P> 78 * When a drag gesture occurs, the 79 * <code>DragSource</code>'s 80 * startDrag() method shall be 81 * invoked in order to cause processing 82 * of the user's navigational 83 * gestures and delivery of Drag and Drop 84 * protocol notifications. A 85 * <code>DragSource</code> shall only 86 * permit a single Drag and Drop operation to be 87 * current at any one time, and shall 88 * reject any further startDrag() requests 89 * by throwing an <code>IllegalDnDOperationException</code> 90 * until such time as the extant operation is complete. 91 * <P> 92 * The startDrag() method invokes the 93 * createDragSourceContext() method to 94 * instantiate an appropriate 95 * <code>DragSourceContext</code> 96 * and associate the <code>DragSourceContextPeer</code> 97 * with that. 98 * <P> 99 * If the Drag and Drop System is 100 * unable to initiate a drag operation for 101 * some reason, the startDrag() method throws 102 * a <code>java.awt.dnd.InvalidDnDOperationException</code> 103 * to signal such a condition. Typically this 104 * exception is thrown when the underlying platform 105 * system is either not in a state to 106 * initiate a drag, or the parameters specified are invalid. 107 * <P> 108 * Note that during the drag, the 109 * set of operations exposed by the source 110 * at the start of the drag operation may not change 111 * until the operation is complete. 112 * The operation(s) are constant for the 113 * duration of the operation with respect to the 114 * <code>DragSource</code>. 115 * 116 * @since 1.2 117 */ 118 119 public class DragSource implements Serializable { 120 121 private static final long serialVersionUID = 6236096958971414066L; 122 123 /* 124 * load a system default cursor 125 */ 126 127 private static Cursor load(String name) { 128 if (GraphicsEnvironment.isHeadless()) { 129 return null; 130 } 131 132 try { 133 return (Cursor)Toolkit.getDefaultToolkit().getDesktopProperty(name); 134 } catch (Exception e) { 135 e.printStackTrace(); 136 137 throw new RuntimeException("failed to load system cursor: " + name + " : " + e.getMessage()); 138 } 139 } 140 141 142 /** 143 * The default <code>Cursor</code> to use with a copy operation indicating 144 * that a drop is currently allowed. <code>null</code> if 145 * <code>GraphicsEnvironment.isHeadless()</code> returns <code>true</code>. 146 * 147 * @see java.awt.GraphicsEnvironment#isHeadless 148 */ 149 public static final Cursor DefaultCopyDrop = 150 load("DnD.Cursor.CopyDrop"); 151 152 /** 153 * The default <code>Cursor</code> to use with a move operation indicating 154 * that a drop is currently allowed. <code>null</code> if 155 * <code>GraphicsEnvironment.isHeadless()</code> returns <code>true</code>. 156 * 157 * @see java.awt.GraphicsEnvironment#isHeadless 158 */ 159 public static final Cursor DefaultMoveDrop = 160 load("DnD.Cursor.MoveDrop"); 161 162 /** 163 * The default <code>Cursor</code> to use with a link operation indicating 164 * that a drop is currently allowed. <code>null</code> if 165 * <code>GraphicsEnvironment.isHeadless()</code> returns <code>true</code>. 166 * 167 * @see java.awt.GraphicsEnvironment#isHeadless 168 */ 169 public static final Cursor DefaultLinkDrop = 170 load("DnD.Cursor.LinkDrop"); 171 172 /** 173 * The default <code>Cursor</code> to use with a copy operation indicating 174 * that a drop is currently not allowed. <code>null</code> if 175 * <code>GraphicsEnvironment.isHeadless()</code> returns <code>true</code>. 176 * 177 * @see java.awt.GraphicsEnvironment#isHeadless 178 */ 179 public static final Cursor DefaultCopyNoDrop = 180 load("DnD.Cursor.CopyNoDrop"); 181 182 /** 183 * The default <code>Cursor</code> to use with a move operation indicating 184 * that a drop is currently not allowed. <code>null</code> if 185 * <code>GraphicsEnvironment.isHeadless()</code> returns <code>true</code>. 186 * 187 * @see java.awt.GraphicsEnvironment#isHeadless 188 */ 189 public static final Cursor DefaultMoveNoDrop = 190 load("DnD.Cursor.MoveNoDrop"); 191 192 /** 193 * The default <code>Cursor</code> to use with a link operation indicating 194 * that a drop is currently not allowed. <code>null</code> if 195 * <code>GraphicsEnvironment.isHeadless()</code> returns <code>true</code>. 196 * 197 * @see java.awt.GraphicsEnvironment#isHeadless 198 */ 199 public static final Cursor DefaultLinkNoDrop = 200 load("DnD.Cursor.LinkNoDrop"); 201 202 private static final DragSource dflt = 203 (GraphicsEnvironment.isHeadless()) ? null : new DragSource(); 204 205 /** 206 * Internal constants for serialization. 207 */ 208 static final String dragSourceListenerK = "dragSourceL"; 209 static final String dragSourceMotionListenerK = "dragSourceMotionL"; 210 211 /** 212 * Gets the <code>DragSource</code> object associated with 213 * the underlying platform. 214 * 215 * @return the platform DragSource 216 * @exception HeadlessException if GraphicsEnvironment.isHeadless() 217 * returns true 218 * @see java.awt.GraphicsEnvironment#isHeadless 219 */ 220 public static DragSource getDefaultDragSource() { 221 if (GraphicsEnvironment.isHeadless()) { 222 throw new HeadlessException(); 223 } else { 224 return dflt; 225 } 226 } 227 228 /** 229 * Reports 230 * whether or not drag 231 * <code>Image</code> support 232 * is available on the underlying platform. 233 * 234 * @return if the Drag Image support is available on this platform 235 */ 236 237 public static boolean isDragImageSupported() { 238 Toolkit t = Toolkit.getDefaultToolkit(); 239 240 Boolean supported; 241 242 try { 243 supported = (Boolean)Toolkit.getDefaultToolkit().getDesktopProperty("DnD.isDragImageSupported"); 244 245 return supported.booleanValue(); 246 } catch (Exception e) { 247 return false; 248 } 249 } 250 251 /** 252 * Creates a new <code>DragSource</code>. 253 * 254 * @exception HeadlessException if GraphicsEnvironment.isHeadless() 255 * returns true 256 * @see java.awt.GraphicsEnvironment#isHeadless 257 */ 258 public DragSource() throws HeadlessException { 259 if (GraphicsEnvironment.isHeadless()) { 260 throw new HeadlessException(); 261 } 262 } 263 264 /** 265 * Start a drag, given the <code>DragGestureEvent</code> 266 * that initiated the drag, the initial 267 * <code>Cursor</code> to use, 268 * the <code>Image</code> to drag, 269 * the offset of the <code>Image</code> origin 270 * from the hotspot of the <code>Cursor</code> at 271 * the instant of the trigger, 272 * the <code>Transferable</code> subject data 273 * of the drag, the <code>DragSourceListener</code>, 274 * and the <code>FlavorMap</code>. 275 * 276 * @param trigger the <code>DragGestureEvent</code> that initiated the drag 277 * @param dragCursor the initial {@code Cursor} for this drag operation 278 * or {@code null} for the default cursor handling; 279 * see <a href="DragSourceContext.html#defaultCursor">DragSourceContext</a> 280 * for more details on the cursor handling mechanism during drag and drop 281 * @param dragImage the image to drag or {@code null} 282 * @param imageOffset the offset of the <code>Image</code> origin from the hotspot 283 * of the <code>Cursor</code> at the instant of the trigger 284 * @param transferable the subject data of the drag 285 * @param dsl the <code>DragSourceListener</code> 286 * @param flavorMap the <code>FlavorMap</code> to use, or <code>null</code> 287 * 288 * @throws java.awt.dnd.InvalidDnDOperationException 289 * if the Drag and Drop 290 * system is unable to initiate a drag operation, or if the user 291 * attempts to start a drag while an existing drag operation 292 * is still executing 293 */ 294 295 public void startDrag(DragGestureEvent trigger, 296 Cursor dragCursor, 297 Image dragImage, 298 Point imageOffset, 299 Transferable transferable, 300 DragSourceListener dsl, 301 FlavorMap flavorMap) throws InvalidDnDOperationException { 302 303 SunDragSourceContextPeer.setDragDropInProgress(true); 304 305 try { 306 if (flavorMap != null) this.flavorMap = flavorMap; 307 308 DragSourceContext dsc = createDragSourceContext(trigger, dragCursor, 309 dragImage, 310 imageOffset, 311 transferable, dsl); 312 313 if (dsc == null) { 314 throw new InvalidDnDOperationException(); 315 } 316 DragSourceContextAccessor acc = AWTAccessor.getDragSourceContextAccessor(); 317 acc.getPeer(dsc).startDrag(dsc, dsc.getCursor(), dragImage, imageOffset); // may throw 318 } catch (RuntimeException e) { 319 SunDragSourceContextPeer.setDragDropInProgress(false); 320 throw e; 321 } 322 } 323 324 /** 325 * Start a drag, given the <code>DragGestureEvent</code> 326 * that initiated the drag, the initial 327 * <code>Cursor</code> to use, 328 * the <code>Transferable</code> subject data 329 * of the drag, the <code>DragSourceListener</code>, 330 * and the <code>FlavorMap</code>. 331 * 332 * @param trigger the <code>DragGestureEvent</code> that 333 * initiated the drag 334 * @param dragCursor the initial {@code Cursor} for this drag operation 335 * or {@code null} for the default cursor handling; 336 * see <a href="DragSourceContext.html#defaultCursor">DragSourceContext</a> 337 * for more details on the cursor handling mechanism during drag and drop 338 * @param transferable the subject data of the drag 339 * @param dsl the <code>DragSourceListener</code> 340 * @param flavorMap the <code>FlavorMap</code> to use or <code>null</code> 341 * 342 * @throws java.awt.dnd.InvalidDnDOperationException 343 * if the Drag and Drop 344 * system is unable to initiate a drag operation, or if the user 345 * attempts to start a drag while an existing drag operation 346 * is still executing 347 */ 348 349 public void startDrag(DragGestureEvent trigger, 350 Cursor dragCursor, 351 Transferable transferable, 352 DragSourceListener dsl, 353 FlavorMap flavorMap) throws InvalidDnDOperationException { 354 startDrag(trigger, dragCursor, null, null, transferable, dsl, flavorMap); 355 } 356 357 /** 358 * Start a drag, given the <code>DragGestureEvent</code> 359 * that initiated the drag, the initial <code>Cursor</code> 360 * to use, 361 * the <code>Image</code> to drag, 362 * the offset of the <code>Image</code> origin 363 * from the hotspot of the <code>Cursor</code> 364 * at the instant of the trigger, 365 * the subject data of the drag, and 366 * the <code>DragSourceListener</code>. 367 * 368 * @param trigger the <code>DragGestureEvent</code> that initiated the drag 369 * @param dragCursor the initial {@code Cursor} for this drag operation 370 * or {@code null} for the default cursor handling; 371 * see <a href="DragSourceContext.html#defaultCursor">DragSourceContext</a> 372 * for more details on the cursor handling mechanism during drag and drop 373 * @param dragImage the <code>Image</code> to drag or <code>null</code> 374 * @param dragOffset the offset of the <code>Image</code> origin from the hotspot 375 * of the <code>Cursor</code> at the instant of the trigger 376 * @param transferable the subject data of the drag 377 * @param dsl the <code>DragSourceListener</code> 378 * 379 * @throws java.awt.dnd.InvalidDnDOperationException 380 * if the Drag and Drop 381 * system is unable to initiate a drag operation, or if the user 382 * attempts to start a drag while an existing drag operation 383 * is still executing 384 */ 385 386 public void startDrag(DragGestureEvent trigger, 387 Cursor dragCursor, 388 Image dragImage, 389 Point dragOffset, 390 Transferable transferable, 391 DragSourceListener dsl) throws InvalidDnDOperationException { 392 startDrag(trigger, dragCursor, dragImage, dragOffset, transferable, dsl, null); 393 } 394 395 /** 396 * Start a drag, given the <code>DragGestureEvent</code> 397 * that initiated the drag, the initial 398 * <code>Cursor</code> to 399 * use, 400 * the <code>Transferable</code> subject data 401 * of the drag, and the <code>DragSourceListener</code>. 402 * 403 * @param trigger the <code>DragGestureEvent</code> that initiated the drag 404 * @param dragCursor the initial {@code Cursor} for this drag operation 405 * or {@code null} for the default cursor handling; 406 * see <a href="DragSourceContext.html#defaultCursor">DragSourceContext</a> class 407 * for more details on the cursor handling mechanism during drag and drop 408 * @param transferable the subject data of the drag 409 * @param dsl the <code>DragSourceListener</code> 410 * 411 * @throws java.awt.dnd.InvalidDnDOperationException 412 * if the Drag and Drop 413 * system is unable to initiate a drag operation, or if the user 414 * attempts to start a drag while an existing drag operation 415 * is still executing 416 */ 417 418 public void startDrag(DragGestureEvent trigger, 419 Cursor dragCursor, 420 Transferable transferable, 421 DragSourceListener dsl) throws InvalidDnDOperationException { 422 startDrag(trigger, dragCursor, null, null, transferable, dsl, null); 423 } 424 425 /** 426 * Creates the {@code DragSourceContext} to handle the current drag 427 * operation. 428 * <p> 429 * To incorporate a new <code>DragSourceContext</code> 430 * subclass, subclass <code>DragSource</code> and 431 * override this method. 432 * <p> 433 * If <code>dragImage</code> is <code>null</code>, no image is used 434 * to represent the drag over feedback for this drag operation, but 435 * <code>NullPointerException</code> is not thrown. 436 * <p> 437 * If <code>dsl</code> is <code>null</code>, no drag source listener 438 * is registered with the created <code>DragSourceContext</code>, 439 * but <code>NullPointerException</code> is not thrown. 440 * 441 * @param dgl The <code>DragGestureEvent</code> that triggered the 442 * drag 443 * @param dragCursor The initial {@code Cursor} for this drag operation 444 * or {@code null} for the default cursor handling; 445 * see <a href="DragSourceContext.html#defaultCursor">DragSourceContext</a> class 446 * for more details on the cursor handling mechanism during drag and drop 447 * @param dragImage The <code>Image</code> to drag or <code>null</code> 448 * @param imageOffset The offset of the <code>Image</code> origin from the 449 * hotspot of the cursor at the instant of the trigger 450 * @param t The subject data of the drag 451 * @param dsl The <code>DragSourceListener</code> 452 * 453 * @return the <code>DragSourceContext</code> 454 * 455 * @throws NullPointerException if <code>dscp</code> is <code>null</code> 456 * @throws NullPointerException if <code>dgl</code> is <code>null</code> 457 * @throws NullPointerException if <code>dragImage</code> is not 458 * <code>null</code> and <code>imageOffset</code> is <code>null</code> 459 * @throws NullPointerException if <code>t</code> is <code>null</code> 460 * @throws IllegalArgumentException if the <code>Component</code> 461 * associated with the trigger event is <code>null</code>. 462 * @throws IllegalArgumentException if the <code>DragSource</code> for the 463 * trigger event is <code>null</code>. 464 * @throws IllegalArgumentException if the drag action for the 465 * trigger event is <code>DnDConstants.ACTION_NONE</code>. 466 * @throws IllegalArgumentException if the source actions for the 467 * <code>DragGestureRecognizer</code> associated with the trigger 468 * event are equal to <code>DnDConstants.ACTION_NONE</code>. 469 */ 470 471 protected DragSourceContext createDragSourceContext(DragGestureEvent dgl, 472 Cursor dragCursor, 473 Image dragImage, 474 Point imageOffset, 475 Transferable t, 476 DragSourceListener dsl) { 477 return new DragSourceContext(dgl, dragCursor, dragImage, imageOffset, t, dsl); 478 } 479 480 /** 481 * This method returns the 482 * <code>FlavorMap</code> for this <code>DragSource</code>. 483 * 484 * @return the <code>FlavorMap</code> for this <code>DragSource</code> 485 */ 486 487 public FlavorMap getFlavorMap() { return flavorMap; } 488 489 /** 490 * Creates a new <code>DragGestureRecognizer</code> 491 * that implements the specified 492 * abstract subclass of 493 * <code>DragGestureRecognizer</code>, and 494 * sets the specified <code>Component</code> 495 * and <code>DragGestureListener</code> on 496 * the newly created object. 497 * 498 * @param <T> the type of {@code DragGestureRecognizer} to create 499 * @param recognizerAbstractClass the requested abstract type 500 * @param actions the permitted source drag actions 501 * @param c the <code>Component</code> target 502 * @param dgl the <code>DragGestureListener</code> to notify 503 * 504 * @return the new <code>DragGestureRecognizer</code> or <code>null</code> 505 * if the <code>Toolkit.createDragGestureRecognizer</code> method 506 * has no implementation available for 507 * the requested <code>DragGestureRecognizer</code> 508 * subclass and returns <code>null</code> 509 */ 510 511 public <T extends DragGestureRecognizer> T 512 createDragGestureRecognizer(Class<T> recognizerAbstractClass, 513 Component c, int actions, 514 DragGestureListener dgl) 515 { 516 return Toolkit.getDefaultToolkit().createDragGestureRecognizer(recognizerAbstractClass, this, c, actions, dgl); 517 } 518 519 520 /** 521 * Creates a new <code>DragGestureRecognizer</code> 522 * that implements the default 523 * abstract subclass of <code>DragGestureRecognizer</code> 524 * for this <code>DragSource</code>, 525 * and sets the specified <code>Component</code> 526 * and <code>DragGestureListener</code> on the 527 * newly created object. 528 * 529 * For this <code>DragSource</code> 530 * the default is <code>MouseDragGestureRecognizer</code>. 531 * 532 * @param c the <code>Component</code> target for the recognizer 533 * @param actions the permitted source actions 534 * @param dgl the <code>DragGestureListener</code> to notify 535 * 536 * @return the new <code>DragGestureRecognizer</code> or <code>null</code> 537 * if the <code>Toolkit.createDragGestureRecognizer</code> method 538 * has no implementation available for 539 * the requested <code>DragGestureRecognizer</code> 540 * subclass and returns <code>null</code> 541 */ 542 543 public DragGestureRecognizer createDefaultDragGestureRecognizer(Component c, int actions, DragGestureListener dgl) { 544 return Toolkit.getDefaultToolkit().createDragGestureRecognizer(MouseDragGestureRecognizer.class, this, c, actions, dgl); 545 } 546 547 /** 548 * Adds the specified <code>DragSourceListener</code> to this 549 * <code>DragSource</code> to receive drag source events during drag 550 * operations initiated with this <code>DragSource</code>. 551 * If a <code>null</code> listener is specified, no action is taken and no 552 * exception is thrown. 553 * 554 * @param dsl the <code>DragSourceListener</code> to add 555 * 556 * @see #removeDragSourceListener 557 * @see #getDragSourceListeners 558 * @since 1.4 559 */ 560 public void addDragSourceListener(DragSourceListener dsl) { 561 if (dsl != null) { 562 synchronized (this) { 563 listener = DnDEventMulticaster.add(listener, dsl); 564 } 565 } 566 } 567 568 /** 569 * Removes the specified <code>DragSourceListener</code> from this 570 * <code>DragSource</code>. 571 * If a <code>null</code> listener is specified, no action is taken and no 572 * exception is thrown. 573 * If the listener specified by the argument was not previously added to 574 * this <code>DragSource</code>, no action is taken and no exception 575 * is thrown. 576 * 577 * @param dsl the <code>DragSourceListener</code> to remove 578 * 579 * @see #addDragSourceListener 580 * @see #getDragSourceListeners 581 * @since 1.4 582 */ 583 public void removeDragSourceListener(DragSourceListener dsl) { 584 if (dsl != null) { 585 synchronized (this) { 586 listener = DnDEventMulticaster.remove(listener, dsl); 587 } 588 } 589 } 590 591 /** 592 * Gets all the <code>DragSourceListener</code>s 593 * registered with this <code>DragSource</code>. 594 * 595 * @return all of this <code>DragSource</code>'s 596 * <code>DragSourceListener</code>s or an empty array if no 597 * such listeners are currently registered 598 * 599 * @see #addDragSourceListener 600 * @see #removeDragSourceListener 601 * @since 1.4 602 */ 603 public DragSourceListener[] getDragSourceListeners() { 604 return getListeners(DragSourceListener.class); 605 } 606 607 /** 608 * Adds the specified <code>DragSourceMotionListener</code> to this 609 * <code>DragSource</code> to receive drag motion events during drag 610 * operations initiated with this <code>DragSource</code>. 611 * If a <code>null</code> listener is specified, no action is taken and no 612 * exception is thrown. 613 * 614 * @param dsml the <code>DragSourceMotionListener</code> to add 615 * 616 * @see #removeDragSourceMotionListener 617 * @see #getDragSourceMotionListeners 618 * @since 1.4 619 */ 620 public void addDragSourceMotionListener(DragSourceMotionListener dsml) { 621 if (dsml != null) { 622 synchronized (this) { 623 motionListener = DnDEventMulticaster.add(motionListener, dsml); 624 } 625 } 626 } 627 628 /** 629 * Removes the specified <code>DragSourceMotionListener</code> from this 630 * <code>DragSource</code>. 631 * If a <code>null</code> listener is specified, no action is taken and no 632 * exception is thrown. 633 * If the listener specified by the argument was not previously added to 634 * this <code>DragSource</code>, no action is taken and no exception 635 * is thrown. 636 * 637 * @param dsml the <code>DragSourceMotionListener</code> to remove 638 * 639 * @see #addDragSourceMotionListener 640 * @see #getDragSourceMotionListeners 641 * @since 1.4 642 */ 643 public void removeDragSourceMotionListener(DragSourceMotionListener dsml) { 644 if (dsml != null) { 645 synchronized (this) { 646 motionListener = DnDEventMulticaster.remove(motionListener, dsml); 647 } 648 } 649 } 650 651 /** 652 * Gets all of the <code>DragSourceMotionListener</code>s 653 * registered with this <code>DragSource</code>. 654 * 655 * @return all of this <code>DragSource</code>'s 656 * <code>DragSourceMotionListener</code>s or an empty array if no 657 * such listeners are currently registered 658 * 659 * @see #addDragSourceMotionListener 660 * @see #removeDragSourceMotionListener 661 * @since 1.4 662 */ 663 public DragSourceMotionListener[] getDragSourceMotionListeners() { 664 return getListeners(DragSourceMotionListener.class); 665 } 666 667 /** 668 * Gets all the objects currently registered as 669 * <code><em>Foo</em>Listener</code>s upon this <code>DragSource</code>. 670 * <code><em>Foo</em>Listener</code>s are registered using the 671 * <code>add<em>Foo</em>Listener</code> method. 672 * 673 * @param <T> the type of listener objects 674 * @param listenerType the type of listeners requested; this parameter 675 * should specify an interface that descends from 676 * <code>java.util.EventListener</code> 677 * @return an array of all objects registered as 678 * <code><em>Foo</em>Listener</code>s on this 679 * <code>DragSource</code>, or an empty array if no such listeners 680 * have been added 681 * @exception ClassCastException if <code>listenerType</code> 682 * doesn't specify a class or interface that implements 683 * <code>java.util.EventListener</code> 684 * 685 * @see #getDragSourceListeners 686 * @see #getDragSourceMotionListeners 687 * @since 1.4 688 */ 689 public <T extends EventListener> T[] getListeners(Class<T> listenerType) { 690 EventListener l = null; 691 if (listenerType == DragSourceListener.class) { 692 l = listener; 693 } else if (listenerType == DragSourceMotionListener.class) { 694 l = motionListener; 695 } 696 return DnDEventMulticaster.getListeners(l, listenerType); 697 } 698 699 /** 700 * This method calls <code>dragEnter</code> on the 701 * <code>DragSourceListener</code>s registered with this 702 * <code>DragSource</code>, and passes them the specified 703 * <code>DragSourceDragEvent</code>. 704 * 705 * @param dsde the <code>DragSourceDragEvent</code> 706 */ 707 void processDragEnter(DragSourceDragEvent dsde) { 708 DragSourceListener dsl = listener; 709 if (dsl != null) { 710 dsl.dragEnter(dsde); 711 } 712 } 713 714 /** 715 * This method calls <code>dragOver</code> on the 716 * <code>DragSourceListener</code>s registered with this 717 * <code>DragSource</code>, and passes them the specified 718 * <code>DragSourceDragEvent</code>. 719 * 720 * @param dsde the <code>DragSourceDragEvent</code> 721 */ 722 void processDragOver(DragSourceDragEvent dsde) { 723 DragSourceListener dsl = listener; 724 if (dsl != null) { 725 dsl.dragOver(dsde); 726 } 727 } 728 729 /** 730 * This method calls <code>dropActionChanged</code> on the 731 * <code>DragSourceListener</code>s registered with this 732 * <code>DragSource</code>, and passes them the specified 733 * <code>DragSourceDragEvent</code>. 734 * 735 * @param dsde the <code>DragSourceDragEvent</code> 736 */ 737 void processDropActionChanged(DragSourceDragEvent dsde) { 738 DragSourceListener dsl = listener; 739 if (dsl != null) { 740 dsl.dropActionChanged(dsde); 741 } 742 } 743 744 /** 745 * This method calls <code>dragExit</code> on the 746 * <code>DragSourceListener</code>s registered with this 747 * <code>DragSource</code>, and passes them the specified 748 * <code>DragSourceEvent</code>. 749 * 750 * @param dse the <code>DragSourceEvent</code> 751 */ 752 void processDragExit(DragSourceEvent dse) { 753 DragSourceListener dsl = listener; 754 if (dsl != null) { 755 dsl.dragExit(dse); 756 } 757 } 758 759 /** 760 * This method calls <code>dragDropEnd</code> on the 761 * <code>DragSourceListener</code>s registered with this 762 * <code>DragSource</code>, and passes them the specified 763 * <code>DragSourceDropEvent</code>. 764 * 765 * @param dsde the <code>DragSourceEvent</code> 766 */ 767 void processDragDropEnd(DragSourceDropEvent dsde) { 768 DragSourceListener dsl = listener; 769 if (dsl != null) { 770 dsl.dragDropEnd(dsde); 771 } 772 } 773 774 /** 775 * This method calls <code>dragMouseMoved</code> on the 776 * <code>DragSourceMotionListener</code>s registered with this 777 * <code>DragSource</code>, and passes them the specified 778 * <code>DragSourceDragEvent</code>. 779 * 780 * @param dsde the <code>DragSourceEvent</code> 781 */ 782 void processDragMouseMoved(DragSourceDragEvent dsde) { 783 DragSourceMotionListener dsml = motionListener; 784 if (dsml != null) { 785 dsml.dragMouseMoved(dsde); 786 } 787 } 788 789 /** 790 * Serializes this <code>DragSource</code>. This method first performs 791 * default serialization. Next, it writes out this object's 792 * <code>FlavorMap</code> if and only if it can be serialized. If not, 793 * <code>null</code> is written instead. Next, it writes out 794 * <code>Serializable</code> listeners registered with this 795 * object. Listeners are written in a <code>null</code>-terminated sequence 796 * of 0 or more pairs. The pair consists of a <code>String</code> and an 797 * <code>Object</code>; the <code>String</code> indicates the type of the 798 * <code>Object</code> and is one of the following: 799 * <ul> 800 * <li><code>dragSourceListenerK</code> indicating a 801 * <code>DragSourceListener</code> object; 802 * <li><code>dragSourceMotionListenerK</code> indicating a 803 * <code>DragSourceMotionListener</code> object. 804 * </ul> 805 * 806 * @serialData Either a <code>FlavorMap</code> instance, or 807 * <code>null</code>, followed by a <code>null</code>-terminated 808 * sequence of 0 or more pairs; the pair consists of a 809 * <code>String</code> and an <code>Object</code>; the 810 * <code>String</code> indicates the type of the <code>Object</code> 811 * and is one of the following: 812 * <ul> 813 * <li><code>dragSourceListenerK</code> indicating a 814 * <code>DragSourceListener</code> object; 815 * <li><code>dragSourceMotionListenerK</code> indicating a 816 * <code>DragSourceMotionListener</code> object. 817 * </ul>. 818 * @since 1.4 819 */ 820 private void writeObject(ObjectOutputStream s) throws IOException { 821 s.defaultWriteObject(); 822 823 s.writeObject(SerializationTester.test(flavorMap) ? flavorMap : null); 824 825 DnDEventMulticaster.save(s, dragSourceListenerK, listener); 826 DnDEventMulticaster.save(s, dragSourceMotionListenerK, motionListener); 827 s.writeObject(null); 828 } 829 830 /** 831 * Deserializes this <code>DragSource</code>. This method first performs 832 * default deserialization. Next, this object's <code>FlavorMap</code> is 833 * deserialized by using the next object in the stream. 834 * If the resulting <code>FlavorMap</code> is <code>null</code>, this 835 * object's <code>FlavorMap</code> is set to the default FlavorMap for 836 * this thread's <code>ClassLoader</code>. 837 * Next, this object's listeners are deserialized by reading a 838 * <code>null</code>-terminated sequence of 0 or more key/value pairs 839 * from the stream: 840 * <ul> 841 * <li>If a key object is a <code>String</code> equal to 842 * <code>dragSourceListenerK</code>, a <code>DragSourceListener</code> is 843 * deserialized using the corresponding value object and added to this 844 * <code>DragSource</code>. 845 * <li>If a key object is a <code>String</code> equal to 846 * <code>dragSourceMotionListenerK</code>, a 847 * <code>DragSourceMotionListener</code> is deserialized using the 848 * corresponding value object and added to this <code>DragSource</code>. 849 * <li>Otherwise, the key/value pair is skipped. 850 * </ul> 851 * 852 * @see java.awt.datatransfer.SystemFlavorMap#getDefaultFlavorMap 853 * @since 1.4 854 */ 855 private void readObject(ObjectInputStream s) 856 throws ClassNotFoundException, IOException { 857 s.defaultReadObject(); 858 859 // 'flavorMap' was written explicitly 860 flavorMap = (FlavorMap)s.readObject(); 861 862 // Implementation assumes 'flavorMap' is never null. 863 if (flavorMap == null) { 864 flavorMap = SystemFlavorMap.getDefaultFlavorMap(); 865 } 866 867 Object keyOrNull; 868 while (null != (keyOrNull = s.readObject())) { 869 String key = ((String)keyOrNull).intern(); 870 871 if (dragSourceListenerK == key) { 872 addDragSourceListener((DragSourceListener)(s.readObject())); 873 } else if (dragSourceMotionListenerK == key) { 874 addDragSourceMotionListener( 875 (DragSourceMotionListener)(s.readObject())); 876 } else { 877 // skip value for unrecognized key 878 s.readObject(); 879 } 880 } 881 } 882 883 /** 884 * Returns the drag gesture motion threshold. The drag gesture motion threshold 885 * defines the recommended behavior for {@link MouseDragGestureRecognizer}s. 886 * <p> 887 * If the system property <code>awt.dnd.drag.threshold</code> is set to 888 * a positive integer, this method returns the value of the system property; 889 * otherwise if a pertinent desktop property is available and supported by 890 * the implementation of the Java platform, this method returns the value of 891 * that property; otherwise this method returns some default value. 892 * The pertinent desktop property can be queried using 893 * <code>java.awt.Toolkit.getDesktopProperty("DnD.gestureMotionThreshold")</code>. 894 * 895 * @return the drag gesture motion threshold 896 * @see MouseDragGestureRecognizer 897 * @since 1.5 898 */ 899 public static int getDragThreshold() { 900 int ts = AccessController.doPrivileged( 901 new GetIntegerAction("awt.dnd.drag.threshold", 0)).intValue(); 902 if (ts > 0) { 903 return ts; 904 } else { 905 Integer td = (Integer)Toolkit.getDefaultToolkit(). 906 getDesktopProperty("DnD.gestureMotionThreshold"); 907 if (td != null) { 908 return td.intValue(); 909 } 910 } 911 return 5; 912 } 913 914 /* 915 * fields 916 */ 917 918 private transient FlavorMap flavorMap = SystemFlavorMap.getDefaultFlavorMap(); 919 920 private transient DragSourceListener listener; 921 922 private transient DragSourceMotionListener motionListener; 923 }